The present invention relates to a biopsy device that takes a biopsy sample of human or animal tissue and delivers a coagulant or other material to the biopsy incision track in order to plug the track and prevent bleeding.
Excision biopsy of the liver has traditionally been the gold standard for assessing the extent of injury and determining prognosis in chronic viral hepatitis and liver cancer. A significant complication that frequently occurs is bleeding from the biopsy site. Significant hemorrhage occurs in 0.35 to 0.5% of all procedures while evidence of sub-clinical bleeding, as detectable by ultrasound 24 hours post biopsy, has been reported in up to 23% of patients. Smaller amounts of surface bleeding is almost universal and is frequently associated with mild to moderate pain.
Excision biopsies from other organs, such as the lungs, also exhibit a relatively high complication rate due to hemorrhagic incidents and pneumothorax. Also with kidney biopsies and biopsies of other organs, perfuse bleeding is considered the most important complication.
The most common liver biopsy technique is by percutaneously inserting a needle into the liver for a fraction of a second and obtaining a tissue sample. The subsequent procedure for taking the biopsy varies according to whether the biopsy needle is of the aspiration or cutting type. For the cutting needle, the needle is inserted into the liver and followed by the outer sheath. The specimen is entrapped in the recessed section of the cutting needle. The aspiration technique is probably the most widely used technique. The best known aspiration biopsy technique is based on the principle indicated by Menghini. There a hollow needle having an average diameter of 1.4 mm and having a facility for attachment of a syringe is used, by which a negative pressure (suction) is applied upon piercing through the skin and prior to the organ puncture proper. The organ puncture (liver) then is realized with a sustained suction to secure the biopsy sample.
In order to obviate the reported complications, it was recommended to subsequently plug the needle track with resorbable material so as to eliminate, in particular, bleeding complications. Such techniques, however, imply a long residence time of the puncture needle in the organ, which again constitutes a cause of complications, in particular with liver punctures.
From Austrian Pat. No. 384,165, a biopsy needle device of the initially defined kind is known, with which the cannula has a curved partition wall towards the internal limitation of the cannula lumina. Therein, the partition wall does not reach immediately to the front end of the cannula so that the biopsy channel and the application channel communicate in the region of the tip of the cannula. The multi-lumen biopsy needle according to Austrian Pat. No. 384,165 enables the collection of tissue and the application of substances plugging the puncture track in coordination with the puncturing procedure in one operating cycle, thus largely shortening the time of intervention.
U.S. Pat. No. 4,850,373 and related EP patents 243341 A, B1 etc., also describes a biopsy needle device having a two lumen cannula, a biopsy channel of constant cross section and one application channel. The application channel is formed by a tube eccentrically slipped over the biopsy channel wall. Furthermore, the biopsy channel is described as a noncircular tubular structure with its channel wall flattened in cross section such that an application channel is formed between the flattened side of the biopsy channel wall and the outer application tube. In addition, surface contact exists between the non-flattened side of the biopsy channel wall and the application tube.
A common surgical material used to control bleeding is Gelfoam(copyright). Gelfoam(copyright) is supplied in either a powder form or as an implantable sponge. Sterile sponges, such as Gelfoam(copyright), are prepared in dry sterile sheets that are used as packing material during surgery for control of bleeding. The sponge sheets are left in the surgical site after surgery to stop bleeding and are absorbed by the body in 1 to 6 weeks. A number of techniques have used these absorbable sterile sponge materials to plug a biopsy track to minimize or prevent bleeding. The absorbable sponge provides a mechanical blockage of the track, encourages clotting, and minimizes bleeding though the biopsy track. Despite the advantages of using absorbable sponge to plug a biopsy track this technique has not achieved widespread use because of difficulty in preparing and delivering the sponge material into the biopsy track.
One example of a biopsy wound closure device using an implantable sponge is described in U.S. Pat. No. 5,388,588. According to this patent, a circular sponge of an absorbable foam material is precut and inserted into a biopsy site by an applicator rod having the sponge positioned on the end. Once the sponge is implanted, the sponge absorbs blood and swells to fill the track preventing further bleeding at the biopsy site. However, the sponge is difficult to deliver and expands slowly once delivered. In addition, this delivery method can only deliver a sponge of a limited size that provides less local compression than desired and may incompletely fill the target site. Further, bleeding may continue along sections of the biopsy track where no sponge has been delivered.
Another example of a Gelfoam(copyright) inserting device to facilitate hemostasis is described in U.S. Pat. No. 6,086,607. According to this patent, a method of cutting a piece of Gelfoam(copyright) sponge from a sheet of the material, folding the strip to form a pledget with one end of different cross section than the other end, and inserting the pledget in an adapter to compress the pledget and for attachment to a syringe for delivery of the pledget to the tissue. The adapter is attached to a cannula that was previously inserted into the organ being biopsied and the Gelfoam(copyright) is inserted into the tissue through the cannula.
No previous patents describe the combination of the multi lumen needle containing a biopsy channel and an application channel with a syringe assembly for obtaining the biopsy and delivering the application material. In addition, the prior art does not describe a biopsy needle that translates within the application tube so that the application material will have an unobstructed passage into the biopsy track. The previous patents either describe the biopsy channel as being eccentrically positioned within the application tube as opposed to the disclosed concentric positioned biopsy or a separate device which delivers a hemostatic sponge to the biopsy track.
The present invention provides a biopsy device with a view to enabling the collection of tissue specimens for biopsy and to apply auxiliary substances directly in the site of the puncture without tissue specimens getting into the application cannula, thus obstructing the same.
In accordance with one aspect of the present invention, a syringe system comprised of a multi chambered unit for taking the biopsy specimen and delivering a coagulating material. The system includes a multi-lumen channel structure with at least one biopsy channel of formed by a tube constant cross section over its entire length and at least one application channel formed by a tube of varying cross section slipped over the biopsy channel wall. The biopsy tube is connected to the end of biopsy syringe and opens to the inner chamber of the system for securing and retrieving the biopsy specimen. The application tube is connected to the end of the outer casing and communicates with the outer chamber containing the application material. When the biopsy syringe is retracted within syringe assembly, the biopsy needle is also retracted within the application channel.
The biopsy channel wall projecting out of the application tube with its cutting edge formed by an acute angularly designed end of the biopsy wall channel.
Using a prior art biopsy device, a biopsy is achieved according to the invention in that after the tissue specimen is collected in the biopsy channel, the inner tube containing the tissue specimen is retracted within the concentric outer application tube thus allowing the application material to be injected into the biopsy track without obstruction. The retraction of the inner, biopsy tube provides the mechanism by which the application material is forced to be expelled from the outer application tube. This is facilitated according to the invention by a placing the biopsy device in another device which causes the translations and movements of the parts of the fore mentioned biopsy device.